The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Vehicle systems including electric and hybrid powertrain systems employ electric power systems using high-voltage and low-voltage energy systems to provide power. Known high-voltage systems include electric machines that are configured to generate tractive torque and reactive driveline torque to generate electric power. Known low-voltage systems include electric machines that are configured to provide power to accessories, e.g., headlamps, air conditioning compressors, and electric power steering devices. Known electric power systems include DC/DC power converters configured to convert high-voltage electric power to low-voltage electric power. Known DC/DC power converters for vehicle systems include high-voltage electric power inputs, for example 330 Vdc, with output power regulated at a reference voltage level commanded at or near 42 Vdc and 12 Vdc. Known electric power systems include low-voltage batteries having nominal voltage outputs of 12 Vdc. Reference voltage levels are predetermined voltage levels that are selected as a function of state of charge and a temperature of a low-voltage battery. Known systems limit an allowable range for a reference voltage level when headlamps are operating. Low-voltage electric power draws and electric power surges in excess of predetermined thresholds can cause either one or both of headlamp flickering and automatic shutdown of a DC/DC converter to protect equipment.